Harbor seals

Sex and age composition of the harbor seals consisted of nine females and 14 males, and 11 pups, five yearlings, and seven adults, respectively. Cause of death was not definitively determined in five of the animals, but in one of these animals was suspected to be due to heavy lungworm infestation. A presumptive diagnosis of abandonment/starvation was made in four animals (pups), trauma due to gunshot wounds in one yearling and four adults and possibly in a six animal (pup). In the animals with signs of starvation, blubber layers were very thin (< 3mm) and the gastrointestinal tracts were empty. In two pups and two yearlings, severe verminous pneumonia was detected. In one male pup a large trichobezor was discovered in the lower large intestine and rectum. A compression fracture of a thoracic vertebra was noted in an adult female who also presented with cachexia at stranding. Possible head trauma was noted in a male pup as evidenced by the fractured caudal portion of the right zygomatic arch. In a female pup, an enlarged liver with accompanying icterus was noted, which was later determined to be caused by a bacteremia due to E. coli.

California sea lion

External examination showed one animal (the male) to be in generally good body condition. The cranium was nearly fully exposed through decomposition and the activity of scavengers. While flensing the limb bones, the right femur was discovered to have a partially healed fracture completely transecting the bone at mid-shaft. No evidence of external scarring was observed during the necropsy, so the cause of this fracture is unknown.

On the second animal, a female, domoic acid toxicity was suspected to be the cause of death. The finding of a female California sea lion in the inland waters of Washington State is considered very unusual, as males are usually the gender that is present in this state.

Harbor porpoise

The harbor porpoise was a yearling female whose cause of death was bronchopneumonia.

Gray whale

The adult male was moderately decomposed and in fair body condition. Significant findings from this examination included a large amount of blood in the body cavity, bruising in some areas of the blubber layer and in some internal organs, and a stomach full of recently ingested prey. These findings are suggestive of blunt force trauma, likely caused by a collision with a large ship. Post mortem decomposition and artifactual sloughing of the mucosa from multiple viscera hindered microscopic assessment of the tissues and precluded precise determination of possible ante mortem trauma or post mortem putrefaction.

December 2007 - May 2008 - The stranding network performed necropsies on two animals: a Steller sea lion in January and a northern elephant seal in May.

Steller sea lion

An adult, male Steller sea lion was found live-stranded in January and subsequently died. Purulent pneumonia was observed on gross necropsy. Samples were submitted for histopathology and culture and are pending.

Northern elephant seal

A moderately decomposed adult male northern elephant seal was found in May.

July - November 2007 - The Central Puget Sound Marine Mammal Stranding Network conducted partial necropsies on 15 harbor seals (Phoca vitulina) spanning the period of July through November 2007. Tissues from a fetus of a harbor porpoise (Phocoena phocoena) necropsied in February 2007 were submitted for histopathologic examination.

Harbor seals

Sex and age composition of the harbor seals consisted of 12 females and 2 males, and 12 pups and two adults, respectively. Cause of death was not definitively determined in three of the animals. A presumptive diagnosis of emaciation/starvation was made in six animals (pups), trauma possibly due to gunshot wounds or boat strike in a male pup and an adult female, ruptured small intestine in two female pups, and probable pneumonia in an adult female. Tissues were not sampled in any of these animals due to budgetary constraints; however, the skulls of the two diagnosed with trauma were collected for further ballistics investigation. Two additional female pups are frozen to be necropsied in the near future.

Harbor porpoise fetus

The fungal organism, Cryptococcus gattii, was isolated from the placenta and ovary of this male fetus’ mother and from the fetus’ mediastinal lymph node, demonstrating the intrauterine infection of this fetus from maternal cryptococcosis. This case represents the index case of fetal cryptococcosis in either animals or humans. This case will be described and submitted to a peer-reviewed journal for publication in the coming year.

Harbor seals

Sex and age composition of the harbor seals consisted of seven females and three males, and three pups, four yearlings, and three adults, respectively. Cause of death was not definitively determined in two of the animals. A presumptive diagnosis of emaciation/starvation was made in three animals (pups), trauma due to gunshot wounds in two yearlings, and an infectious etiology in the remainder. In one of the latter pups, bacterial culture of several internal organs yielded a significant heavy growth of Escherichia coli that was believed to have been a contributory factor in the loss of the animal. In a second animal, Streptococcus phocae was isolated from an aerobic culture of intestinal tract which may have lead to septicemia. Recently, this pathogen has been recovered in the Pacific Northwest from harbor seals an occasional harbor porpoises with evidence of localized abscessation or generalized sepsis (S. Raverty, unpub data). Abscessation and fasciitis of the left side of the head and neck, mostly likely secondary to a penetrating wound, and leading to a probable secondary septicemia, was documented in an adult harbor seal. Finally, an adult animal was found to have pleuropneumonia, suspected to be due to either a primary bacterial infection or secondary to some other underlying condition.

Harbor porpoises

In 2006 there was a marked increase in harbor porpoise strandings in the Pacific Northwest of the United States. By the end of 2006, 63 stranded harbor porpoise had been reported in the inland waters and outer coasts of Washington and Oregon, which was nearly twice the previous maximum number of annual harbor porpoise strandings for the region (34 in 2003) (NOAA Fisheries, unpub. data). After consultation with the Working Group on Marine Mammal Unusual Mortality Events, an Unusual Mortality Event (UME) was declared on 3 November 2006 to facilitate the coordination of response and investigative efforts. An additional 14 have been recorded in 2007 as of mid-July 2007, for a total of 77. The majority of strandings (78%) occurred in Washington State, with the remainder in Oregon. The unusual rate of mortality does not appear to extend into British Columbia or California. Northwest Marine Mammal Stranding Network participants responded to and examined 69 porpoises. Of these, detailed necropsies were performed on 48, 6 were frozen and are pending examination, and 13 received external examinations only (some with limited sample collection). Two porpoises stranded live and were immediately released. The overall cause of the mortality increase has not been determined and the investigation is ongoing.

CPSMMSN participated in the UME investigating and conducted necropsies on several UME-related harbor porpoises. Four females and five males comprised the sex distribution, while the age class composition consisted of five calves/neonates, one yearling/juvenile, 1 subadult, and two adults. Trauma accounted for the death of four of the harbor porpoises (one of which may also have been afflicted with bronchopneumonia), infectious/inflammatory causes for three deaths, parasitic for one, and undetermined causes for the remaining two. Fetal distress-type syndrome (presence of meconium particles in lung parenchyma) was noted in a calf which may have been due to physical trauma. A second calf had traumatic lesions (multisystemic hemorrhage) that may have been incurred at the time of parturition (dystocia). A third calf displayed signs of possible trauma; however, bronchopneumonia was also documented which was severe enough to account for loss of this animal. A generalized septicemia was documented in a fourth calf. The subadult porpoise had a verminous pneumonia severe enough to have impaired respiratory function, potentially leading to the animal’s death. One of the adults had a profound bronchopneumonia that significantly impaired respiratory function. In addition, intravascular protozoa were discovered in the lung that may be suggestive of either Sarcocystis neurona, Toxoplasma gondii, or some other apicomplexa. Cryptococcus gattii was documented in two adult females, one of which was collected and necropsied by another stranding organization and is not discussed further in this summary. The other cryptococcosis female was pregnant with a male 22cm fetus whose tissues are currently being analyzed. In addition, tissue analysis is still pending on one of the adult males.

Gray whales

The male yearling gray whale was necropsied in situ and showed signs of severe dehydration and emaciation, accompanied by marked, extensive pediculosis. There was severe extensive, acute hemorrhage and edema of the throat, paralumbar and inguinal musculature suggestive of primary trauma. There were presumptive bite wounds to the skin of the flukes and flippers which may have been inflicted by killer whales. Lastly, there was subcutaneous abscessation of the right axilla which may have been secondary to a deep wound.